.flex-demo {
  padding: 20px;
  font-family: Arial, sans-serif;
}

.controls {
  margin-bottom: 20px;
}

.controls button {
  margin-right: 10px;
  padding: 6px 10px;
  border: 1px solid #ccc;
  background: #e71f1f;
  cursor: pointer;
  border-radius: 4px;
}

.container {
  display: flex;
  align-items: center;
  height: 200px;
  background-color: #f0f0f0;
  border: 2px solid #ccc;
}

.item {
  width: 60px;
  height: 60px;
  display: flex;
  justify-content: center;
  align-items: center;
  color: #fff;
  font-size: 24px;
  font-weight: bold;
  border-radius: 8px;
  margin: 5px;
}

.item1 {
  background-color: #f5f;
}

.item2 {
  background-color: #4ecdc4;
}

.item3 {
  background-color: #1a535c;
}